643339565 has 16 divisors (see below), whose sum is σ = 845916480. Its totient is φ = 465822160.

The previous prime is 643339531. The next prime is 643339573. The reversal of 643339565 is 565933346.

It is not a de Polignac number, because 643339565 - 2⁸ = 643339309 is a prime.

Its product of digits (874800) is a multiple of the sum of its prime divisors (243).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2833982 + ... + 2834208.

It is an arithmetic number, because the mean of its divisors is an integer number (52869780).

Almost surely, 2^643339565 is an apocalyptic number.

It is an amenable number.

643339565 is a deficient number, since it is larger than the sum of its proper divisors (202576915).

643339565 is an frugal number, since it uses more digits than its factorization.

643339565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 697 (or 243 counting only the distinct ones).

The product of its digits is 874800, while the sum is 44.

The square root of 643339565 is about 25364.1393506659. The cubic root of 643339565 is about 863.2702085928.

The spelling of 643339565 in words is "six hundred forty-three million, three hundred thirty-nine thousand, five hundred sixty-five".